LAUSR

The origin of the matter–antimatter asymmetry of the universe remains unexplained in the Standard Model (SM) of particle physics. The origin of the flavour structure is another major puzzle of the theory. In this article, we report on recent work attempting to link the two themes through the appealing framework of electroweak (EW) baryogenesis. We show that Yukawa couplings of SM fermions can be the source of CP violation for EW baryogenesis if they vary at the same time as the Higgs is acquiring its vacuum expectation value, offering new avenues for EW baryogenesis. The advantage of this approach is that it circumvents the usual severe bounds from electric dipole moments. These ideas apply if the mechanism explaining the flavour structure of the SM is connected to EW symmetry breaking, as motivated for instance in Randall–Sundrum or Composite Higgs models. We compute the resulting baryon asymmetry for different configurations of the Yukawa coupling variation across the bubble wall and show that it can naturally be of the right order. This article is part of the Theo Murphy meeting issue ‘Higgs cosmology’.